1. Field of the Invention
The present invention relates to apparatus employing adjustment means for axially aligning pairs of articles, and more particularly, to an apparatus for aligning the core cross-sectional area of one optical component with that of another optical component, or with a center line of another optical component.
2. Description of the Prior Art
When coupling pairs of optical conductors for minimum light signal distortion and attenuation, it is necessary to align accurately the light carrying cores of the optical conductors. Core alignment is essential since light signal propagation occurs primarily in the cores and not in the surrounding cladding which is used primarily to provide optical insulation and protection. In most alignment procedures, it is possible to obtain alignment symmetry of the outer jacket of two conductors and yet still have axial misalignment of the inner cores. Similar problems are inherent in attempting to align an inner core of an optical conductor with a centerline of another optical component, such as an emitter or a detector.
One method of aligning the core of one optical conductor with that of another utilizes an eccentric coupler as described in an article entitled "Eccentric Coupler for Optical Fibers: a Simplified Version" by S. Zemon, et al., published in Applied Optics, April 1975, Vol. 14, No. 4, at page 815. This coupler comprises a V-block metal housing; a pair of sleeve-capillary units, each unit fabricated to be inserted into the ends of the V-block; and a shim affixed on the wall at one end of the V-block to cause the axis of one of the sleeves to be offset. The pair of conductors to be aligned are inserted and glued in the capillaries, and the sleeve-capillary units are installed on the V-block so as to cause the ends of the conductors to abut one another.
In operation, the alignment is accomplished by rotating the sleeve-capillary units about axes that are offset from each other. With an appropriate choice of offset dimensions, the two circles traced out by the rotating conductors intersect at two points whereat the conductor-to-conductor interface is optimized.
Although this coupler can be used to align axially the cores of two conductors, the alignment process appears to be a tedious and complicated process. To find one of the two intersecting positions without the benefit of having means for performing a cursory or coarse alignment of the conductors appears to be a matter of conjecture. Also, upon rotating both of the conductors to either of the two intersecting positions, confusion may arise as to which position provides the best alignment. Further, no structural elements are provided to optimize the alignment procedures to compensate for nonuniformity of the cross-sectional areas of the abutting core surfaces.